Field of the Disclosure
The present disclosure relates to a display device, and more particularly, to a display device having a mirror function.
Discussion of the Related Art
With rapid development of information technologies, display devices for displaying a large amount of information have been promptly developed. More particularly, flat panel display (FPD) devices having a thin profile, light weight and low power consumption such as organic electroluminescent display (OLED) devices and liquid crystal display (LCD) devices have been actively pursued and widely applied.
Recently, display devices further having a mirror function in addition to an image display function have been suggested and actively developed. That is, in on-state, the display device displays an image, and in off-state, the display device functions as a mirror.
For the mirror function, the display device includes a half mirror glass at a side where an image is displayed.
The half mirror glass has a mirror surface effect by depositing metal oxide on a surface of a glass substrate. The half mirror glass reflects some of light and transmits the other of light. By the way, since the half mirror glass has transmittance of about 40%, the half mirror glass decreases the brightness of the display device.
Particularly, when the display device is a liquid crystal display device, an upper polarizer of the liquid crystal display device has transmittance of about 43%, and the total transmittance of the upper polarizer and the half mirror glass is about 17.2%. Thus, the brightness of the liquid crystal display device including the half mirror glass is very low.
Moreover, since the half mirror glass has a thickness of about 3 mm, which is thicker than a display panel, a thickness of the display device increases due to the half mirror glass.
Furthermore, the half mirror glass is mechanically fixed to the display device, the thickness of the display device further increases. In addition, the manufacturing process is complicated, and manufacturing apparatus and materials are added to thereby increase manufacturing costs. At this time, since there exists an air gap between the half mirror glass and the display device and light is scattered, several images are generated, and image qualities are lowered.